JP2015147156A - Apparatus and method for treating water containing iron/manganese - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus for treating water containing iron/manganese, in which the amount of an oxidation catalyst to be used can be reduced drastically and the height of an oxidation tank can also be suppressed in comparison with the conventional apparatuses, and to provide a method for treating water containing iron/manganese.SOLUTION: The apparatus for treating water containing iron/manganese includes: an oxidizer tank 18 for adding an oxidizer to water containing iron/manganese, in which water at least one of iron and manganese is contained; the oxidation tank 12 which is used for oxidizing by feeding the oxidizer-added water and in which the manganese dioxide-containing oxidation catalyst is packed; and a membrane filtration unit 14 for filtering the oxidized water by using a membrane. The water passage SV (space velocity) of the oxidation tank 12 is controlled within a range of 100-300 (l/h) and the membrane to be used in the membrane filtration unit has 0.03 μm or smaller pore diameter.

Description

  The present invention relates to a treatment apparatus and treatment method for iron / manganese-containing water used in water purification plants and the like.

  River water, groundwater, etc., which are water sources, may contain soluble iron and soluble manganese. As a method of removing soluble iron and soluble manganese in iron / manganese-containing water containing at least one of iron and manganese, a contact manganese sand filtration method is known. The contact manganese sand filtration method is a method in which soluble manganese is oxidized and precipitated and trapped in manganese sand while raw water is passed through the manganese sand oxidation treatment tank in a downward flow.

  In addition, as a method for performing high-speed treatment of iron / manganese-containing water, an oxidation treatment tank filled with an oxidation catalyst containing manganese dioxide is added to an iron / manganese-containing water while adding an oxidizing agent such as chlorine, for example, 1,000 m / Pass water as an upward flow at a high linear velocity of more than a day to oxidize and precipitate iron and manganese in the raw water, and filter the water passing through this oxidation treatment tank through a ceramic MF membrane (pore diameter 0.1 μm) (See, for example, Patent Documents 1 and 2). Compared with the conventional contact manganese sand filtration method, this method can pass raw water through the oxidation treatment tank at a high linear velocity, so the equipment can be downsized and there is less blockage due to turbidity in the raw water. Therefore, there is an advantage that the cleaning frequency of the oxidation treatment tank can be reduced.

  However, as in Patent Document 1, in the method of filtering the passing water of the oxidation treatment tank with a ceramic MF membrane, the water supply entity often sets the manganese content concentration of the treated water as the target treated water quality. When trying to make the value less than 005 mg / L, the water flow SV of the oxidation treatment tank has to be about 100 (1 / h), and there is a problem that the amount of catalyst used increases. In addition, with the increase in the amount of catalyst used, there is also a problem that the height of the oxidation treatment tank increases.

Japanese Patent No. 3705590 Japanese Patent No. 3786888

  An object of the present invention is to provide a treatment apparatus and treatment method for iron / manganese-containing water that can significantly reduce the amount of oxidation catalyst used and can suppress the height of the oxidation treatment tank. It is in.

  The present invention provides an oxidizing agent adding means for adding an oxidizing agent to iron / manganese-containing water containing at least one of iron and manganese, and manganese dioxide for oxidizing the oxidizing agent-added water to which the oxidizing agent is added. An oxidation treatment tank filled with an oxidation catalyst containing, and a membrane filtration means for membrane-filtering the oxidation-treated water subjected to oxidation treatment, and a water flow SV of the oxidation treatment tank is 100 to 300 (1 / h) The membrane used for the membrane filtration is an iron / manganese-containing water treatment apparatus having a pore size of 0.03 μm or less.

Moreover, in the said iron / manganese containing water processing apparatus, it is preferable that the said water flow SV is below SV calculated | required by following Formula (1) according to a process target water quality.
Water flow SV = (target water quality + 0.01) ÷ 0.00005 Formula (1)

  Moreover, this invention contains manganese dioxide, the oxidizing agent addition process which adds an oxidizing agent to the iron / manganese containing water containing at least 1 among iron and manganese, and the oxidizing agent addition water to which the said oxidizing agent was added An oxidation treatment step of passing through an oxidation treatment tank filled with an oxidation catalyst to oxidize, and a membrane filtration step of membrane-filtering the oxidized treatment water; However, it is the range of 100-300 (1 / h), and the film | membrane used for the said membrane filtration is a processing method of the iron / manganese containing water which is a film | membrane with a pore diameter of 0.03 micrometer or less.

Moreover, in the said iron / manganese containing water processing method, it is preferable that the said water flow SV is below SV calculated | required by following Formula (1) according to a process target water quality.
Water flow SV = (target water quality + 0.01) ÷ 0.00005 Formula (1)

  In the present invention, in the treatment of iron / manganese-containing water, the water flow SV of the oxidation treatment tank is in the range of 100 to 300 (1 / h), and the membrane used for membrane filtration is a membrane having a pore diameter of 0.03 μm or less. As a result, the amount of the oxidation catalyst used can be significantly reduced as compared with the conventional apparatus, and the apparatus height of the oxidation treatment tank can be suppressed.

It is a schematic block diagram which shows an example of the processing apparatus of the iron / manganese containing water which concerns on embodiment of this invention. It is a figure which shows the relationship between the water flow SV and the treated water manganese density | concentration in an Example.

  Embodiments of the present invention will be described below. This embodiment is an example for carrying out the present invention, and the present invention is not limited to this embodiment.

  An outline of an example of the iron / manganese-containing water treatment apparatus according to the embodiment of the present invention is shown in FIG. The iron / manganese-containing water treatment device 1 includes an oxidation treatment tank 12 filled with an oxidation catalyst containing manganese dioxide, and a membrane filtration device 14 as membrane filtration means. The iron / manganese-containing water treatment apparatus 1 may include a raw water tank 10 and a treated water tank 16.

  In the iron / manganese-containing water treatment apparatus 1, a raw water pipe 26 is connected to an inlet of the raw water tank 10, and an outlet of the raw water tank 1 and a lower inlet of the oxidation treatment tank 12 are connected to a raw water supply pipe via a pump 20. 28, the upper outlet of the oxidation treatment tank 12 and the inlet of the membrane filtration device 14 are connected by an oxidation treatment water pipe 30, and the outlet of the membrane filtration device 14 and the inlet of the treatment water tank 16 are treated water piping 32. A treated water discharge pipe 34 is connected to the outlet of the treated water tank 16. The lower part of the treated water tank 16 is connected to the treated water pipe 32 in the middle by a backwash pipe 36 via the pump 22. In the middle of the raw water supply pipe 28, an outlet of the oxidant tank 18 as an oxidant addition means is connected by an oxidant supply pipe 38 via a pump 24.

  The operation of the iron / manganese-containing water treatment method and the iron / manganese-containing water treatment apparatus 1 according to the present embodiment will be described.

  The iron / manganese-containing water containing at least one of iron and manganese, which is raw water, is stored in the raw water tank 10 through the raw water pipe 26 as needed, and then the oxidation treatment tank 12 through the raw water supply pipe 28 by the pump 20. The liquid is sent to. At this time, oxidant is added to the raw water from the oxidant tank 18 through the oxidant supply pipe 38 by the pump 24 in the middle of the raw water supply pipe 28 (oxidant addition process), and is supplied to the oxidation treatment tank 12 as oxidant added water. The liquid is sent. In the present embodiment, the oxidant tank 18, the pump 24, and the oxidant supply pipe 38 function as an oxidant addition unit. The addition of the oxidant to the raw water may be performed in the raw water tank 10, or a separate oxidant mixing tank is provided between the raw water tank 10 and the oxidation treatment tank 12, and is performed in the oxidant mixing tank. It may be broken.

  In the oxidation treatment tank 12, a catalyst layer is formed by an oxidation catalyst containing manganese dioxide, and the oxidant-added water is passed through the catalyst layer by an upward flow and is oxidized by an oxidation catalyst containing manganese dioxide (oxidation treatment step). ). While the oxidizing agent is added to the iron / manganese-containing water, water is passed through the oxidation treatment tank 12 filled with the oxidation catalyst containing manganese dioxide, so that dissolved iron and dissolved manganese are oxidized and precipitated.

  Oxidized water that has undergone oxidation treatment is sent to the membrane filtration device 14 through the oxidation treatment water pipe 30, and precipitates such as iron and manganese that are oxidized and precipitated in the membrane filtration device 14 are filtered and removed (membrane filtration). Process).

  The membrane-filtered treated water is sent to the treated water tank 16 through the treated water pipe 32 and stored. When at least a part of the treated water in the treated water tank 16 is discharged out of the system through the treated water discharge pipe 34 and the membrane of the membrane filtration device 14 needs to be cleaned, at least a part of the treated water is supplied by the pump 22. The liquid may be fed from the outlet side to the membrane filtration device 14 through the backwash pipe 36 and used for backwashing the membrane filtration device 14 (backwashing step). The backwash drainage is discharged from the backwash drain outlet through the backwash drain pipe 40.

  In this embodiment, while adding an oxidizing agent to iron / manganese-containing water, water is passed through an oxidation treatment tank 12 filled with an oxidation catalyst containing manganese dioxide, so that dissolved iron and dissolved manganese are oxidized and precipitated. In the treatment of iron / manganese-containing water for membrane filtration of the oxidation-treated water, the water flow SV of the oxidation treatment tank 12 is in the range of 100 to 300 (1 / h), and membrane filtration has a pore size of 0.03 μm or less, preferably Uses a UF membrane with a pore size of 0.01 μm.

  By using a membrane having a pore size of 0.03 μm or less, preferably a UF membrane having a pore size of 0.01 μm, as the membrane filtration device 14 subsequent to the oxidation treatment tank 12, it is difficult to remove with an MF membrane (pore size 0.1 μm). Since the fine manganese particles that have existed can also be removed, a better quality of treated water can be obtained. Since the manganese particle diameter in the oxidation-treated water tends to decrease as the water flow SV in the oxidation treatment tank 12 increases, for example, in the operation method described in Patent Document 1, the water flow SV in the oxidation treatment tank is set to 100. Even if the treated water quality is less than 0.005 mg / L, the treated water quality becomes 0.005 mg / L or more in the case of SV200. On the other hand, when a membrane having a pore size of 0.03 μm or less, preferably a UF membrane having a pore size of 0.01 μm, is used in the membrane filtration device 14 subsequent to the oxidation treatment bath 12, the water flow SV of the oxidation treatment bath 12 is set to 200 However, the manganese particle diameter in the oxidation-treated water becomes 0.01 μm or more, and it is possible to sufficiently achieve the treated water quality of less than 0.005 mg / L.

  The water flow SV of the oxidation treatment tank 12 is in the range of 100 to 300 (1 / h). When the water flow SV of the oxidation treatment tank 12 is less than 100 (1 / h), the amount of catalyst used increases and the height of the apparatus increases, and when it exceeds 300 (1 / h), the treated water quality is 0.005 mg. / L may be exceeded.

Further, when the target treated water quality is not so severe, it is possible to change the water flow SV according to the water quality, and it is possible to further reduce the amount of catalyst used and the apparatus height of the oxidation treatment tank 12. The water flow SV can be determined from the following equation (1), and the relationship with the target treated water quality is as shown in Table 1.
Water flow SV = (treatment target water quality + 0.01) ÷ 0.00005 Formula (1)

  Examples of the oxidizing agent include sodium hypochlorite, bleached powder, potassium permanganate, chlorine dioxide and the like, and sodium hypochlorite is preferable from the viewpoint of running cost, versatility and the like.

  The amount of oxidant added is, for example, in the range of 0.5 mol to 2 mol with respect to 1 mol of iron for soluble iron in iron / manganese-containing water, The range is from 1 mol to 4 mol with respect to 1 mol of manganese content. If the addition amount of the oxidizing agent is less than the above value, the reaction may be insufficient. If it is excessively added, the cost may be disadvantageous and the amount of trihalomethane generated may increase.

  Examples of the oxidation catalyst containing manganese dioxide used in the oxidation treatment tank 12 include an oxidation catalyst in which manganese dioxide is granular and solid, manganese sand, and the like. Further, the manganese dioxide is not particularly limited, and examples thereof include manganese dioxide having α-type, β-type, ε-type, γ-type, λ-type, δ-type, and R-type crystal structures. From this point, manganese dioxide having a β-type crystal structure is preferable.

  In the oxidation treatment tank 12, the oxidation catalyst containing manganese dioxide is in an upward flow, and raw water is passed through the catalyst layer to be in a fluid state to form an expanded bed.

The density of the oxidation catalyst containing manganese dioxide is preferably 2.8 g / cm ³ or more. When the density of the oxidation catalyst containing manganese dioxide is less than 2.8 g / cm ³ , the catalyst develops when water is passed at high speed, and the tank height of the oxidation treatment tank 12 may increase.

  The particle diameter of the oxidation catalyst containing manganese dioxide is preferably in the range of 0.4 mm to 2.0 mm. If the particle size of the oxidation catalyst containing manganese dioxide is less than 0.4 mm, the rate of expansion of the catalyst may increase, and particles having a small particle size may flow out. Efficiency may be reduced.

  The reaction temperature in the oxidation treatment tank 12 is, for example, in the range of 1 ° C to 50 ° C.

  The filtration membrane used in the membrane filtration device 14 is a membrane having a pore size of 0.03 μm or less, and is preferably a UF membrane having a pore size of 0.01 μm or less.

  The iron / manganese-containing water to be treated contains at least one of iron and manganese, preferably contains at least manganese, and usually contains both iron and manganese. The content of soluble iron in the iron / manganese-containing water is, for example, in the range of 0.1 to 10 mg / L, and the content of soluble manganese is, for example, in the range of 0.01 to 5 mg / L.

  Examples of the iron / manganese-containing water to be treated include river water, groundwater, lake water, and the like.

  The treatment apparatus and treatment method for iron / manganese-containing water according to the present embodiment can be suitably applied in, for example, a water purification plant, groundwater use water treatment, and the like.

  Hereinafter, although an example and a comparative example are given and the present invention is explained more concretely in detail, the present invention is not limited to the following examples.

By changing the filling amount of the oxidation catalyst containing manganese dioxide in the oxidation treatment tank, the relationship between the water flow SV and the manganese particle size of the oxidation treatment water was confirmed. As an oxidation catalyst containing manganese dioxide, manganese oxide particles having a β-type crystal structure having a particle size (effective diameter) of 0.5 mm and a density of 4.0 g / cm ³ are used, and the manganese oxide particles are used in a column (φ26 mm × 2000 mm). And a catalyst layer was formed, and water was passed in an upward flow at a flow rate of 1,200 m / day. The raw water manganese concentration was 0.5 mg / L, and sodium hypochlorite was injected as an oxidizing agent so that the residual chlorine concentration was 0.4 mg / L. Oxidized water was filtered through filters having pore sizes of 1.0, 0.20, 0.10, and 0.01 μm, respectively, and the manganese concentration of the treated water was measured. The results are shown in FIG.

  It was found that the higher the water flow SV in the oxidation treatment tank, the more manganese particles with a small particle size increase in the treated water. When the target treated water manganese concentration was less than 0.001 mg / L, when a 0.1 μm filter equivalent to MF membrane filtration was used, the target could not be achieved when SV100 was exceeded, but it was equivalent to UF membrane filtration. When the 0.01 μm filter was used, the target could be achieved even with SV200.

  That is, it can be confirmed that the use of this apparatus makes it possible to realize an iron / manganese-containing water treatment apparatus and treatment method capable of significantly reducing the amount of oxidation catalyst used and suppressing the height of the apparatus compared to the conventional apparatus. It was.

  In addition, from the manganese concentration of φ <0.01 μm in Table 2 and the value of the water flow SV, an approximate straight line is obtained for the relationship between the treatment target water quality and the water flow SV when the UF membrane is used, and the above equation (1) is used. It was found that the treatment target water quality can be achieved by passing water below the calculated SV. It was found that the amount of oxidation catalyst used can be further reduced if the target water quality is not so strict.

  DESCRIPTION OF SYMBOLS 1 Iron / manganese containing water processing apparatus, 10 Raw water tank, 12 Oxidation processing tank, 14 Membrane filtration apparatus, 16 Treated water tank, 18 Oxidant tank, 20, 22, 24 Pump, 26 Raw water piping, 28 Raw water supply piping, 30 Oxidation Treated water piping, 32 treated water piping, 34 treated water discharge piping, 36 backwash piping, 38 oxidant supply piping, 40 backwash drainage piping.

Claims (4)

An oxidizing agent adding means for adding an oxidizing agent to iron / manganese-containing water containing at least one of iron and manganese;
An oxidation treatment tank filled with an oxidation catalyst containing manganese dioxide, which oxidizes the oxidant-added water to which the oxidant is added;
A membrane filtration means for membrane filtration of the oxidized treated water;
With
The water flow SV of the oxidation treatment tank is in the range of 100 to 300 (1 / h),
A treatment apparatus for iron / manganese-containing water, wherein the membrane used for the membrane filtration is a membrane having a pore size of 0.03 μm or less. The iron / manganese-containing water treatment apparatus according to claim 1,
The said water flow SV is below the SV calculated | required by following Formula (1) according to a process target water quality, The iron / manganese containing water processing apparatus characterized by the above-mentioned.
Water flow SV = (target water quality + 0.01) ÷ 0.00005 Formula (1) An oxidizing agent adding step of adding an oxidizing agent to iron / manganese-containing water containing at least one of iron and manganese;
An oxidation treatment step in which the oxidant-added water to which the oxidant is added is passed through an oxidation treatment tank filled with an oxidation catalyst containing manganese dioxide, and is oxidized.
A membrane filtration step for membrane filtration of the oxidized treated water;
Including
The water flow SV of the oxidation treatment tank is in the range of 100 to 300 (1 / h),
A method for treating iron / manganese-containing water, wherein the membrane used for membrane filtration is a membrane having a pore size of 0.03 μm or less. It is a processing method of the iron / manganese containing water of Claim 3, Comprising:
The method of treating iron / manganese-containing water is characterized in that the water flow SV is equal to or less than SV obtained by the following equation (1) according to the treatment target water quality.
Water flow SV = (target water quality + 0.01) ÷ 0.00005 Formula (1)